[Professor Batty]

I don't think I could sell anyone on the Q using abstruse theories.

[sherrvonne]

When I am with my friends, and I have the K3, I hand one of them the yellow Q7 set on auto, I tell them it's cute but not cheapie, give them a couple of simple instructions and watch them have a great time with it. Their reactions to it and their subjects reactions to it is a lot of fun. The next question a lot of them have is where do you buy one of those?

[Tony Belding]

If light is cropped out, that means the total amount of light on the sensor is reduced. The light per mm2 is the same, which is why you can use the same ISO setting, but assuming you are concerned with the photo as a whole, that's hardly relevant. A smaller sensor will show more noise than a larger sensor if you don't adjust the exposure to keep the amount of light that actually hits the sensor equal (meaning more light per mm2).

This all amounts to an overly complicated way of explaining that small sensors don't have the high-ISO performance of larger sensors. I think most of us are well aware of that. So, if you put a K-mount 100mm f/2.8 lens on your Q-S1, it's still a f/2.8 lens. It's "slower" only in the sense that you can't crank up the ISO speed as much on the Q-S1 as you could on a DSLR.

---------- Post added 07-18-15 at 09:47 PM ----------

Going to the original question of how to sell someone on the Q system. . .

I got my Q7 Premium Kit not long ago, and it's fantastic being able to carry an entire kit in such a tiny bag. I can take it anywhere, and I don't have to decide which lenses to bring along. They all come! It's also very good ergonomically. The user interface is very easy to get used to. As so many have said, it's fun to use. It was also a bargain, compared with putting together an equivalent M4/3 system.

However, I've got to say that the Q system catalog is starting to show some signs of neglect, and the competition from Micro Four Thirds is getting strong. The new breed of ultra-compact M4/3 bodies and lenses are starting to make the Q system look bad. It needs updating, and we need some new lenses. Where's that telephoto macro lens that's been on the roadmap for two years?

Unfortunately, the Q system is a bit of a minor sideline for Pentax, while M4/3 is the central product category of both Olympus and Panasonic. They are pouring far more resources into developing their catalogs, and it's hard to see that changing any time soon.

[reh321]

If light is cropped out, that means the total amount of light on the sensor is reduced. The light per mm2 is the same, which is why you can use the same ISO setting, but assuming you are concerned with the photo as a whole, that's hardly relevant. A smaller sensor will show more noise than a larger sensor if you don't adjust the exposure to keep the amount of light that actually hits the sensor equal (meaning more light per mm2).

Of course this doesn't mean you can't enjoy photos you get from this setup, and it may be very good in terms of value-for-money. But saying your 70-300/4-5.6 is suddenly a 330-1400/4-5.6 because you have a smaller sensor behind it, doesn't add up. You have to apply equivalence to both the focal length and the aperture.

Your cannot change truth by hitting it with an avalanche of words, technical or common. I am more impressed by what I see than by your logic and calculations. The truth is, as seen in my Q7, is that I'm getting the equivalence of a 4.7X teleconverter in image, but I'm losing less brightness than I would lose with a 2X teleconverter, and all of this at a relatively small cost. I don't know where this effect comes from. Perhaps from concentrating pixels on the sensor, perhaps from improvements in hardware or software, perhaps it is just magic.

Or you stop saying it's equivalent to anything and just enjoy taking photos with your setup. Which is far more important anyway. .

But we need words to explain what we are seeing, and "equivalent" is the best I can do. If you have another way of describing a picture that would normally require a seriously "long" /expensive lens or an impressive teleconverter, then that is fine, but I believe "equivalent" expresses the truth I've experienced.

added thought: Maybe this whole discussion fits into the "bumblebees can't fly genre".

---

Last edited by reh321; 07-18-2015 at 08:15 PM. Reason: added thought

[starbase218]

I wonder, after these words, if there's any point in posting more on my part. I sense you feel irritated by me, maybe even offended, and you react to that. And maybe I should let this go and leave you be. But I have no quibble with you as a person, and your shots may be fantastic. What I'm trying to say is that your shots can be fantastic, even if they're taken at the equivalent of something like 1400mm, f/26 and ISO 102400. What I'm also trying to say is that those numbers may not matter so much.

Your cannot change truth by hitting it with an avalanche of words, technical or common. I am more impressed by what I see than by your logic and calculations.

If that is so, then why do you feel the need to tell people you are shooting with an equivalent 1400mm f/5.6 lens? Maybe I'm alone in this, but I don't understand the need for people to claim something that is not correct. At the end of the day, your shots will not improve from it, will they?

The truth is, as seen in my Q7, is that I'm getting the equivalence of a 4.7X teleconverter in image, but I'm losing less brightness than I would lose with a 2X teleconverter, and all of this at a relatively small cost. I don't know where this effect comes from. Perhaps from concentrating pixels on the sensor, perhaps from improvements in hardware or software, perhaps it is just magic.

Maybe the relative ISO performance of the Q7's sensor is really good? After all, it is a BSI sensor.

But we need words to explain what we are seeing, and "equivalent" is the best I can do. If you have another way of describing a picture that would normally require a seriously "long" /expensive lens or an impressive teleconverter, then that is fine, but I believe "equivalent" expresses the truth I've experienced.

Truth and personal experience are two very different things. In my opinion, experience is what matters most. But truth can provide insights and help you understand certain things better. The simple facts are, you are not getting the DoF of an f/5.6 lens at 1400mm, and you are probably not too far from diffraction limits (maybe diffraction is already occurring). So it's more than just noise.

I'm going to repeat myself: all of this doesn't mean that you can't enjoy your photos, and that you can't create wonderful shots. Because that has nothing to do with any of this stuff: ISO, aperture, diffraction limits or noise.

I understand the problem of not being able to accurately communicate the capabilities of your setup. If the photographic world would come up with a relative ISO rating that has a codependence on sensor size, then maybe you'd be more inclined to say you shoot at the equivalent of 1400mm and f/26. And maybe it would reflect your experiences better too. That's the problem really. The photographic vocabulary is too limited right now to accurately tell the whole story.

Or let's just keep it simple: show the pictures, then show the camera. This may be the best way to "sell" someone on the Pentax Q.

So what do you know, truth has provided even an answer to the question originally posted in this topic.

[reh321]

I wonder, after these words, if there's any point in posting more on my part. I sense you feel irritated by me, maybe even offended, and you react to that. And maybe I should let this go and leave you be. But I have no quibble with you as a person, and your shots may be fantastic. What I'm trying to say is that your shots can be fantastic, even if they're taken at the equivalent of something like 1400mm, f/26 and ISO 102400. What I'm also trying to say is that those numbers may not matter so much.

If that is so, then why do you feel the need to tell people you are shooting with an equivalent 1400mm f/5.6 lens? Maybe I'm alone in this, but I don't understand the need for people to claim something that is not correct. At the end of the day, your shots will not improve from it, will they?

Maybe the relative ISO performance of the Q7's sensor is really good? After all, it is a BSI sensor.

Truth and personal experience are two very different things. In my opinion, experience is what matters most. But truth can provide insights and help you understand certain things better. The simple facts are, you are not getting the DoF of an f/5.6 lens at 1400mm, and you are probably not too far from diffraction limits (maybe diffraction is already occurring). So it's more than just noise.

I'm going to repeat myself: all of this doesn't mean that you can't enjoy your photos, and that you can't create wonderful shots. Because that has nothing to do with any of this stuff: ISO, aperture, diffraction limits or noise.

I understand the problem of not being able to accurately communicate the capabilities of your setup. If the photographic world would come up with a relative ISO rating that has a codependence on sensor size, then maybe you'd be more inclined to say you shoot at the equivalent of 1400mm and f/26. And maybe it would reflect your experiences better too. That's the problem really. The photographic vocabulary is too limited right now to accurately tell the whole story.

Or let's just keep it simple: show the pictures, then show the camera. This may be the best way to "sell" someone on the Pentax Q.

So what do you know, truth has provided even an answer to the question originally posted in this topic.

If I sound irritated, it is because you persist in using this mathematical f/26 construct (another two times in the post above) I would never be inclined to use that language because it conveys false meaning to someone having actual experience; that is, it would totally misrepresent my experience. From your words, including in the post above, I'm fairly sure that you yourself have no experience with what we are talking about.

I got my first 35mm camera, a totally manual camera, in 1969, so I have almost 50 years of experience with adjustable cameras. I 'm not sure how much is a result of my backgound as a mathematician and how much is a result of that experience, but I have a very clear instinctual grasp of f-stops, and every fiber of that understanding gets vertigo when you repeat that f/26, because the implications are so inconsistent with what I actually see. f/26 tells me that I will need perfect conditions (which isn't going to happen here in the snow-belt of Indiana so close to Lake Michigan), or totally unreasonable ISO, to have any hope of getting a decent image; that is false, as setting my lens at f/5.6 does give me shutter speeds more consistent with f/8 than with anything else. f/26 tells me that I can forget about getting bokeh, pleasing or otherwise, so I need to be very careful about the background because essentially everything back there will be in focus; that is also false. Small sensor cameras like the Q family are known for giving lots of depth-of-field, even if you wanted bokeh, but setting my lens at f/5.6 does give me depth-of-field more consistent with f/5.6 than anything else; f/26 should mean that manual focusing my lens would be trivial, but I had to get the focus right-on or else have a blurry image, and with the bird feeder fifty feet from me, the embankment at most another 20 feet beyond was very definitely in the land of bokeh.

So, I don't tell people, "this camera makes my Sigma lens behave like a 330-1400mm f/26 lens". I don't mention f-stops at all, because that would convey more mis-information than anything else. What I do tell people is, "this camera makes my Sigma lens behave like a 330-1400 lens", because that accurately conveys to them that I can sit, huddled in the cold fifty feet from the bird-feeder, and have that feeder fill the frame. And, yes, I do enjoy using this camera, because that depends only on what I see and experience, not upon the math that leads to false despair.

[starbase218]

Right, all has suddenly become very clear to me. I can't say anything because I don't use the camera like you do and I don't have 50 years experience. And all of this because you are of the opinion that it conveys false meaning. I have nothing more to say here.

See ya.

[reh321]

Right, all has suddenly become very clear to me. I can't say anything because I don't use the camera like you do and I don't have 50 years experience. And all of this because you are of the opinion that it conveys false meaning. I have nothing more to say here.

See ya.

You are entitled to whatever opinion you want to have.

My experience simply means that I understand the implications of your words to others, and how they would give a totally false impression to others.
Your lack of experience with the camera means that you are clinging to conclusions that have no connection to actual real life.
That is fact, not opinion.
You are right that there is no reason to continue this discussion

[Mothballs]

Right, all has suddenly become very clear to me. I can't say anything because I don't use the camera like you do and I don't have 50 years experience. And all of this because you are of the opinion that it conveys false meaning. I have nothing more to say here.

See ya.

I've been sitting on the sidelines and my opinion is that while the math makes sense for calculating equivalent DOF (F26) It's rubbish for telling how much actual light is hitting the sensor. The total volume of light per mm^2 of sensor has not changed, so shutter speed will remain virtually the same as the lens on a APS-C or FF.

The issue that Saying "Oh, it makes the lens f26 Eqiv." Is that my immediate thought is "Holy shit, that's slow." Most thoughts will be "Why do I want a 1000+mm Pinhole lens?" and "That's totally useless."

EVEN IF how you're using the math is correct, the fact that common knowledge (even if incorrect) states that f2 is f2 is f2 for any lens on any sensor means telling someone that it makes it slower (increase in F-number = Less light = Slower shutter) is probably not a good idea.

Also, you're horridly off topic. On the topic, saying this about the f-stop will definitely not sell the camera, and possibly cause a downturn in sales.

The in camera B&W JPGs are very crisp and I rather like them, and I would totally say that it makes a great B&W street camera because of this, the huge DoF and it's small size.

[BrianR]

f/26 tells me that I can forget about getting bokeh, pleasing or otherwise, so I need to be very careful about the background because essentially everything back there will be in focus; that is also false. Small sensor cameras like the Q family are known for giving lots of depth-of-field, even if you wanted bokeh, but setting my lens at f/5.6 does give me depth-of-field more consistent with f/5.6 than anything else; f/26 should mean that manual focusing my lens would be trivial, but I had to get the focus right-on or else have a blurry image, and with the bird feeder fifty feet from me, the embankment at most another 20 feet beyond was very definitely in the land of bokeh.

I don't really want to step in the middle of this discussion, but I want to point out that the magnification (to the sensor and then to the print) influences the DoF as well, and a 1400mm lens would still have one heck of a lot of magnification at 50' away. So, don't try to directly translate the experience of f/22 (or higher) on 35mm (or aps-c) if you've mostly used standard focal length lenses (say 200mm or less) with how a 1400mm @ f/26 would render DoF and out of focus backgrounds on a FF camera.

Here's a calculator to play with, just try out your bird feeder example with the 300mm/5.6 on the Q and the hypothetical 1400/26 on a FF and compare the DoF:

Lens Magnification and Depth of Field Calculator

Dof doesn't tell the whole story, so here's a background blur calculator with these two examples already thrown in for you (I took 30cm as a rough guess of the size of the object you're photographing): How much blur? - A visual background blur calculator

[starbase218]

I don't really want to step in the middle of this discussion, but I want to point out that the magnification (to the sensor and then to the print) influences the DoF as well, and a 1400mm lens would still have one heck of a lot of magnification at 50' away. So, don't try to directly translate the experience of f/22 (or higher) on 35mm (or aps-c) if you've mostly used standard focal length lenses (say 200mm or less) with how a 1400mm @ f/26 would render DoF and out of focus backgrounds on a FF camera.

I looked up the very same calculations right after reh321s last post. But you know what? We are both wrong. What matter is not the facts, but reh321s opinion that f/26 conveys false meaning. We should all adhere to that. Maybe we'll call f/26 f/11. That sounds better, right, reh321?

But even if the facts are like we say they are, the fact that I am 34 years old means that it still doesn't matter. Not when reh321 has 50 years of experience. He knows best. How stupid of me that I did not see that.

FWIW, the Youtube videos from Blunty (e.g.

You Tube

You Tube

) made me curious about the Q series and made me get one. That and seeing one in the store, next to other mirrorless cameras. I never got it until I saw it. So that's how I got sold on the concept. Well, not actually sold, since I think it's too expensive to buy new. But I got one used and I do love it.

[BrianR]

I looked up the very same calculations right after reh321s last post. But you know what? We are both wrong. What matter is not the facts, but reh321s opinion that f/26 conveys false meaning. We should all adhere to that. Maybe we'll call f/26 f/11. That sounds better, right, reh321?

But even if the facts are like we say they are, the fact that I am 34 years old means that it still doesn't matter. Not when reh321 has 50 years of experience. He knows best. How stupid of me that I did not see that.

I've zero interest in joining your insult parade.

Thanks for understanding.

[reh321]

I looked up the very same calculations right after reh321s last post. But you know what? We are both wrong. What matter is not the facts, but reh321s opinion that f/26 conveys false meaning. We should all adhere to that. Maybe we'll call f/26 f/11. That sounds better, right, reh321?

But even if the facts are like we say they are, the fact that I am 34 years old means that it still doesn't matter. Not when reh321 has 50 years of experience. He knows best. How stupid of me that I did not see that.

The only relevance of my experience is that I am confident in my opinion of what will impress other photographers. My opinion, which is what is requested by implication by the "how would you" in the title of this thread, is that most photographers would find this whole discussion of effective f-stops to be many words, full of sound and fury signifying nothing. What they actually care about is what the camera can do ... and that is where I got onto this carousel; for perhaps $600 at current new prices (mine was more like $400 at Black Friday prices), one can put together a system which can take pictures which would have required a 1400mm lens on 35mm camera, and you still get the characteristics (light and bokeh) that would come with an f/5.6 lens. That last statement is a matter of fact, and factual experience is how one should be selling the Pentax Q.

That is why I bought my Q-7, and that is how I would try to sell it to others, the topic of this thread.
Your experience and what you would say to others may differ, and that is just fine with me.

You may continue to talk if you want.
I have stated my facts, based on actual experience.

[6BQ5]

How about we put numbers aside and concentrate on the photographs!

https://www.pentaxforums.com/forums/136-pentax-q/299950-q7-perfect-travel-cam...ny-images.html

[reh321]

How about we put numbers aside and concentrate on the photographs!

https://www.pentaxforums.com/forums/136-pentax-q/299950-q7-perfect-travel-cam...ny-images.html

Yes!

Thank you.